Rearrangement of Hydroxylated Pinene Derivatives to Fenchone-Type Frameworks: Computational Evidence for Dynamically-Controlled Selectivity
作者:Marcus Blümel、Shota Nagasawa、Katherine Blackford、Stephanie R. Hare、Dean J. Tantillo、Richmond Sarpong
DOI:10.1021/jacs.8b05804
日期:2018.7.25
An acid-catalyzed Prins/semipinacolrearrangementcascade reaction of hydroxylated pinene derivatives that leads to tricyclic fenchone-type scaffolds in very high yields and diastereoselectivity has been developed. Quantum chemical analysis of the selectivity-determining step provides support for the existence of an extremely flat potential energy surface around the transition state structure. This
A mesoporous aluminosilicate (Al-MCM-41) was found to be an effective heterogeneous catalyst for the reaction of both aldehydes and acetals with silylenolethers or ketene silylacetals to give the corresponding aldol adducts in moderate to high yields. The remarkable high catalytic activity of Al-MCM-41 over amorphous silica-alumina and aluminum-free mesoporous silicate was observed in the reaction
A new generation of aprotic yet Brønsted acidic imidazolium salts: low toxicity, high recyclability and greatly improved activity
作者:Lauren Myles、Rohitkumar G. Gore、Nicholas Gathergood、Stephen J. Connon
DOI:10.1039/c3gc40975a
日期:——
Catalysts which have low antimicrobial toxicity and are aprotic, yet which can act as Brønsted acidic catalysts in the presence of protic additives have been developed. The catalysts are recyclable, considerably more active (i.e. can be used at 10–50 times lower loadings) and of broader scope than their antecedent generation.
Nickel‐Catalyzed Chemoselective Acetalization of Aldehydes With Alcohols under Neutral Conditions
作者:Murugan Subaramanian、Vinod G. Landge、Akash Mondal、Virendrakumar Gupta、Ekambaram Balaraman
DOI:10.1002/asia.201900908
日期:2019.12.13
A molecularly defined NiII -complex catalyzing the chemoselective acetalization of aldehydes with alcohols underneutralconditions is reported. The reaction is general, efficient and showed a wide substrate scope (including aliphatic aldehydes) as well as excellent functional group tolerance. Reusability of the present nickel catalyst is also demonstrated.
Highly recyclable, imidazolium derived ionic liquids of low antimicrobial and antifungal toxicity: A new strategy for acid catalysis
作者:Lauren Myles、Rohitkumar Gore、Marcel Špulák、Nicholas Gathergood、Stephen J. Connon
DOI:10.1039/c003301d
日期:——
Imidazolium derived ionic liquid catalysts have been developed which are aprotic and of low antimicrobial and antifungal toxicity, yet which can act as efficient Brønsted acidic catalysts in the presence of protic additives. The catalysts can be utilised at low loadings and can be recycled 15 times without any discernible loss of activity.